Ghahremani, E. (2017). Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties. Journal of Applied and Computational Mechanics, (), -. doi: 10.22055/jacm.2017.22206.1128

Esmaeil Ghahremani. "Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties". Journal of Applied and Computational Mechanics, , , 2017, -. doi: 10.22055/jacm.2017.22206.1128

Ghahremani, E. (2017). 'Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties', Journal of Applied and Computational Mechanics, (), pp. -. doi: 10.22055/jacm.2017.22206.1128

Ghahremani, E. Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties. Journal of Applied and Computational Mechanics, 2017; (): -. doi: 10.22055/jacm.2017.22206.1128

Transient Natural Convection in an Enclosure with Variable Thermal Expansion Coefficient and Nanofluid Properties

^{}Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Islamic Republic of Iran

Abstract

Transient natural convection is numerically investigated in an enclosure using variable thermal conductivity, viscosity, and the thermal expansion coefficient of Al2O3-water nanofluid. The study has been conducted for a wide range of Rayleigh numbers (10^{3}≤ Ra ≤ 10^{6}), concentrations of nanoparticles (0% ≤ ϕ ≤ 7%), the enclosure aspect ratio (AR =1), and temperature differences between the cold and hot walls (∆T= 30). Transient parameters such as development time and time-average Nusselt number along the cold wall are also presented as a non-dimensional form. Increasing the Rayleigh number shortens the non-dimensional time of the initializing stage. By increasing the volume fraction of nanoparticles, the flow development time shows different behaviors for various Rayleigh numbers. The non-dimensional development time decreases by enhancing the concentration of nanoparticles.

[1] Ghahremani, E., Ghaffari, R., Ghadjari, H., Mokhtari, J., Effect of variable thermal expansion coefficient and nanofluid properties on steady natural convection in an enclosure, Journal of Applied and Computational Mechanics, 3(4), 2017, pp. 240-250.

[2] Xuan, Y., Roetzel, W., Conceptions for heat transfer correlation of nanofluids, International Journal of Heat and Mass Transfer,43, 2000, pp. 3701–3707.

[3] Khanafer, K., Vafai, K., Lightstone, M., Buoyancy-driven heat transfer enhancement in a two-dimensional enclosure utilizing nanofluids, International Journal of Heat and Mass Transfer,46, 2003, pp. 3639–3653.

[4] Gosselin, L., da Silva, A. K., Combined heat transfer and power dissipation optimization of nanofluid flows”, Applied Physics Letters, 85, 2004, pp. 4160–4162.

[5] Brinkman, H. C., The viscosity of concentrated suspensions and solutions, Journal of Chemical Physics, 20, 1952, pp. 571–581.

[6] Polidori, G., Fohanno, S., Nguyen, C. T., A note on heat transfer modeling of Newtonian nanofluids in laminar free convection, International Journal of Thermal Sciences,46, 2007, pp. 739–744.

[7] Ho, C. J., Chen, M. W., Li, Z. W., Numerical simulation of natural convection of nanofluid in a square enclosure: Effects due to uncertainties of viscosity and thermal conductivity, International Journal of Heat and Mass Transfer, 51, 2008, pp. 4506–4516.

[8] Maiga, S. E. B., Nguyen, C. T., Galanis, N., Roy, G., Heat transfer behaviors of nanofluids in a uniformly heated tube, Superlattices and Microstructures,35, 2004, pp. 543–557.

[9] Aminossadati, S. M., Ghasemi, B., Natural convection of water–CuO nanofluid in a cavity with two pairs of heat source–sink, International Communications in Heat and Mass Transfer,38, 2011, pp. 672–678.

[10] Koo, J., Kleinstreuer, C., A new thermal conductivity model for nanofluids, Journal of Nanoparticle Research,6(6), 2004, pp. 577–588.

[11] Koo, J., Kleinstreuer, C., Laminar nanofluid flow in micro heat-sinks, International Journal of Heat and Mass Transfer,48(13), 2005, pp. 2652–2661.

[12] Abu-Nada., E., Chamkha, A. J., Effect of nanofluid variable properties on natural convection in enclosures filled with a CuO–EG–water nanofluid, International Journal of Thermal Sciences, 49(12), 2010, pp. 2339-2352.

[13] Sheikholeslami, M., Ellahi, R., Hassan, M., Soleimani, S., A study of natural convection heat transfer in a nanofluid filled enclosure with elliptic inner cylinder, International Journal of Numerical Methods for Heat & Fluid Flow, 24(8), 2014, pp. 1906-1927.

[14] Leal, M. A., Machado, H. A., Cotta, R. M., Integral transform solutions of transient natural convection in enclosures with variable fluid properties, International Journal of Heat and Mass Transfer, 43(21), 2000, pp. 3977-3990.

[15] Yu, Z. -T., Wang, W., Xu, X., Fan, L. -W., Hu, Y. -C., Cen, K. -F., A numerical investigation of transient natural convection heat transfer of aqueous nanofluids in a differentially heated square cavity, International Communications in Heat and Mass Transfer, 38, 2011, pp. 585–589.

[16] Yu, Z. -T., Xu, X., Hu, Y. -C., Fan, L. -W., Cen, K. -F., A numerical investigation of transient natural convection heat transfer of aqueous nanofluids in a horizontal concentric annulus, International Journal of Heat and Mass Transfer, 55, 2012, pp. 1141–1148.

[17] Rahman, M. M., Oztop, H. F., Mekhilef, S., Saidur, R., Al-Salem, K., Unsteady natural convection in Al2O3–water nanoliquid filled in isosceles triangular enclosure with sinusoidal thermal boundary condition on bottom wall, Superlattices and Microstructures, 67, 2014, pp. 181–196.

[18] Alsabery, A. I., Saleh, H., Hashim, I., Siddheshwar, P.G., Nanoliquid-Saturated Porous Oblique Cavity using Thermal Non-Equilibrium Model, International Journal of Mechanical Sciences, 114, 2016, pp. 233-245.

[19] Nguyen, M. T., Aly, A. M., Lee, S.-W., Unsteady natural convection heat transfer in a nanofluid-filled square cavity with various heat source conditions, Advances in Mechanical Engineering, 8(5), 2016, pp. 1–18.

[20] Patankar, S. V., Numerical Heat Transfer and Fluid Flow, Hemisphere Publishing Corporation, Taylor and Francis Group, New York, 1980.

[21] Versteeg, H. K., Malalasekera, W., An Introduction to Computational Fluid Dynamic: The Finite Volume Method, John Wiley & Sons Inc., New York, 1995.